Goullons specialized in watch movements with painted enamel cases, including one for King Louis XIV. This case exterior’s miniatures depict the Virgin and Child with an angel, copying an engraving by Pierre Daret, and Joseph being awakened by an angel, after an engraving by Michel Dorigny. These engravings recorded paintings by Simon Vouet. Such enameled watchcases are rarely signed, and the best enamelers were so adept at reproducing the style of their sources that individual masters are difficult to identify.